Variability in Arabidopsis thaliana chromosomal high-mobility-group-1-like proteins.
The vertebrate high-mobility-group (HMG) protein HMG1 is an abundant non-histone protein which is considered as an architectural element in chromatin. In the monocotyledonous plant maize, four different HMG1-like proteins (HMGa, HMGc1/2, HMGd) have been identified, whereas other eukaryotes usually express only two different proteins of this type. We have examined here the HMG1-like proteins of the dicotyledonous plant Arabidopsis thaliana. The isolation and analysis of cDNAs encoding five different so far uncharacterised HMG1-like proteins (now termed HMG alpha, HMG beta1/2, HMG gamma, HMG delta) from Arabidopsis indicates that the expression of multiple HMG1-like proteins is a general feature of (higher) plants. The Arabidopsis HMG1-like proteins contain an HMG domain as a common feature, but outside this conserved DNA-binding motif the amino acid sequences are significantly different indicating that this protein family displays a greater structural variability in plants than in other eukaryotes. The five HMG1-like proteins were expressed in Escherichia coli and purified. They bind with somewhat different affinity to linear double-stranded DNA. The recognition of DNA structure is evident from their preferential interaction with DNA minicircles relative to linear DNA. Reverse-transcribed PCR suggested that the five HMG1-like genes are simultaneously expressed in Arabidopsis leaves and suspension culture cells.
Stemmer
C
C
Institut für Biologie III, Albert-Ludwigs-Universität Freiburg, Germany.
Ritt
C
C
Igloi
G L
GL
Grimm
R
R
Grasser
K D
KD
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000737:chemistry*; D002478:Cells, Cultured; D002482:Cellulose / Q000378:metabolism; D002843:Chromatin / Q000737:chemistry; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry*; D003001:Cloning, Molecular; D017124:Conserved Sequence / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D006609:High Mobility Group Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000032:analysis / Q000737:chemistry; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; D010940:Plant Proteins; D011994:Recombinant Proteins; D002482:Cellulose